050
FXUS66 KOTX 200809
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
109 AM PDT Fri Jun 20 2025

.KEY MESSAGES...

- Big pattern change heading into the weekend with much cooler
  temperatures and rain showers.

- Chance of thunderstorms over the northern mountains Friday,
  Sunday, and Monday

&&

.SYNOPSIS...
A pattern shift arrives Friday into the weekend delivering much
cooler temperatures and rain showers. In addition, there will be
a chance of thunderstorms over the northern mountains at times
Friday through Monday.

&&

.DISCUSSION...
Today through Monday: A big pattern change is coming is a large
closed low barrels through the region. This morning the low is
off the Washington coast with a band of showers developing
across Central Idaho. Models continue to depict this area
expanding this morning with rain showers expect to move into the
Camas Prairie and Central Panhandle Mountains, possibly
extending as far west as Moscow and Lewiston. For this
afternoon as the low moves into SW WA/NW OR the atmosphere will
become increasingly unstable over North Central WA courtesy of
afternoon sunbreaks and cooling aloft with the incoming low. The
NBM continue to advertise a 20-30% chance of thunderstorms for
the Okanogan and Methow Valleys and surrounding high terrain, as
well as areas near the Canadian border. The cold advection with
the low will also lead to breezy winds especially in Central
WA. Tonight the low tracks along the WA/OR border before
rapidly pushing into NW Montana on Saturday. Models continue to
show the highest regional POP`s on Saturday as moisture wraps
around the backside of the low into Eastern Washington and North
Idaho. On Sunday and Monday as the low moves out, the region
remains under the influence of a long wave trough with
additional impulses dropping into the region. Afternoon heating
combined with some lift from these will kick off another round
of showers, but with better instability as well with the ECMWF
advertising 500-1000 J/KG of surface based CAPE over the
northern mountains. Ensembles are painting a rather wet
scenario this weekend for the northern mountains, with a 80-90%
chance of at least 0.50" of rain for Colville and Sandpoint.

Here are the latest NBM 72 hour probabilities of precipitation
amounts receiving various thresholds ending 5 AM Monday:

City            .10+"   .25+"   .50+"   1.00+"   1.50+"
Spokane          90%     75%     45%     10%       0%
Omak             95%     90%     70%     20%       5%
Colville        100%     95%     85%     35%       5%
Sandpoint       100%     95%     90%     65%      40%
Wenatchee        60%     20%      5%      0%       0%
Moses Lake       60%     35%     15%      0%       0%
Pullman          80%     50%     10%      0%       0%
Lewiston         80%     40%      5%      0%       0%

Tuesday through Thursday: Ensembles are in good agreement that
warmer and drier conditions develop as a short wave ridge moves
over the region Tuesday and Wednesday. Will have to watch a
potential short wave dampening the ridge on Thursday which may
produce a few showers especially near the Cascade crest and
along the Canadian border but confidence is low. JW

&&

.AVIATION...
06Z TAFS: VFR conditions are expected to continue for all TAF
sites through 06z Saturday. Winds will start to pick up in the
lee of the Cascades after 06z with speeds at KEAT around 15-20
kts. A band of precipitation will form over northeast OR around
tonight and move north towards KLWS-KCOE bringing a 20-40%
chance for showers between 12z-20z. KPUW-KGEG- KSFF have a
10-20% chance to get brushed by this round of showers. Friday
afternoon instability showers will be on the increase around the
region, but remaining isolated/scattered in coverage over most
areas outside of the mountains. There is also a 20% chance of
afternoon thunderstorms for Chelan, Winthrop, Omak, Republic,
and the surrounding mountains.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
for VFR conditions through 06z Saturday. JW

-----------------------

Confidence descriptors:

Low - Less than a 30 percent chance
Moderate - 30 to 70 percent chance
High - Greater than a 70 percent chance

For additional probabilistic information for NWS Spokane airports,

please refer to the Aviation Dashboard on our webpage:
https:/www.weather.gov/otx/avndashboard

&&

.Preliminary Point Temps/PoPs...
Spokane        68  45  57  46  66  48 /  20  20  70  60  50  40
Coeur d`Alene  67  44  55  44  64  49 /  40  40  80  80  60  50
Pullman        62  43  57  42  62  42 /  30  20  40  60  50  20
Lewiston       71  48  67  50  70  51 /  40  30  30  60  50  10
Colville       69  45  56  44  64  39 /  60  70 100  80  90  70
Sandpoint      65  45  54  44  62  48 /  50  70 100  90  80  80
Kellogg        61  42  51  45  59  49 /  70  50  80  90  70  50
Moses Lake     73  48  66  49  74  50 /  20  20  50  40  40  20
Wenatchee      70  52  66  52  73  53 /  30  30  50  40  40  10
Omak           73  46  64  48  71  49 /  80  80  80  70  70  40

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...None.
ID...None.

&&

$$